I think a lot of the reason that all this death by fucking and general nasty behaviour in the animal world has take this long to come to light is because all those Victorian explorers refused to write it down when they saw it. One of the major complaints levelled against Darwin's theories was that most people believed that the animal kingdom was inherently 'nice' and 'proper' and he was saying no, it's red in tooth and claw.

Some years back I saw some Attenborough thing about British garden birds, and it showed a scene where a male sparrow knocks up a female then flies off, another male comes over and uses his beak to remove the previous males sperm from the female before having a go himself. This repeats with several more males.

If you live in Europe, you'll be familiar with that cute little bird, commonly seen in gardens and feeding stations :

The tits’ behaviour was not opportunistic: they specifically searched for hibernating bats, using both auditory and visual cues, and then pulled them out of their roosting cavities and pecked them to death [see gory photo below]